Evaluation of the anti-inflammatory and analgesic activity of Me-UCH9, a dual cyclooxygenase-2/5-lipoxygenase inhibitor

Recently, we reported the dual inhibition of cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LO) activity by some phenylsulphonyl urenyl chalcone derivatives. 2,4-dichloro-4'N[N'(4'methylphenylsulphonyl)urenyl] chalcone (Me-UCH9), was selected in the present study to determine its potential anti-inflammatory and analgesic effect after oral administration in several animal models related to the activation of COX-2 and 5-LO pathways. In the zymosan stimulated mouse air pouch model, Me-UCH9, reduced in a dose-dependent manner leukotriene B(4) (LTB(4)) levels in pouch exudates obtained at 4 h, as well as prostaglandin E(2) (PGE(2)) generated through COX-2 activation at 24 h. Tumor necrosis factor alpha (TNF-alpha) and myeloperoxidase activity were also strongly inhibited in this model. Me-UCH9 significantly reduced granuloma size and vascular index determined in the murine air pouch granuloma model of angiogenesis. In the carrageenan-induced paw edema, this compound inhibited inflammatory response and pain, as well as PGE(2) and LTB(4) content in paw edematous fluid. Analgesic properties were corroborated in the murine phenyl-p-benzoquinone-induced writhing test. Finally, Me-UCH9 exerted anti-inflammatory effects in the chronic model of rat adjuvant-induced arthritis, both inhibiting paw swelling and reducing PGE(2) content. Our findings confirm that Me-UCH9 can modulate inflammatory and nociceptive responses in relation to the dual inhibition of COX-2 and 5-LO activities presented by this compound.     

Novel di-tertiary-butyl phenylhydrazones as dual cyclooxygenase-2/5-lipoxygenase inhibitors: Synthesis,COX/LOX inhibition,molecular modeling,and insights into their cytotoxicities

Although dual inhibition of Cyclooxygenase-2 (COX-2) and 5-Lipoxygenase (5-LOX) enzymes is highly effective than targeting COX or LOX alone, there are only a few reports of examining such compounds in case of colorectal cancers (CRC). In the present work we report that the novel di-tert-butyl phenol-based dual inhibitors DTPSAL, DTPBHZ, DTPINH, and DTPNHZ exhibit significant cytotoxicity against human CRC cell lines. Molecular docking studies revealed a good fit of these compounds in the COX-2 and 5-LOX protein cavities. The inhibitors show significant inhibition of COX-2 and 5-LOX activities and are effective against a panel of human colon cancer cell lines including HCA-7, HT-29, SW480 and intestinal Apc10.1 cells as well as the hyaluronan synthase-2 (Has2) enzyme over-expressing colon cancer cells, through inhibition of the Hyaluronan/CD44v6 cell survival pathway. Western blot analysis and qRT-PCR analyses indicated that the di-tert-butyl phenol-based dual inhibitors reduce the expression of COX-2, 5-LOX, and CD44v6 in human colon cancer HCA-7 cells, while the combination of CD44v6shRNA and DTPSAL has an additional inhibitory effect on CD44v6 mRNA expression. The synergistic inhibitory effect of Celecoxib and Licofelone on CD44v6 mRNA expression suggests that the present dual inhibitors down-regulate cyclooxygenase and lipoxygenase enzymes through CD44v6. The compounds also exhibited enhanced antiproliferative potency compared to standard dual COX/LOX inhibitor, viz. Licofelone. Importantly, the HA/CD44v6 antagonist CD44v6shRNA in combination with synthetic compounds had a sensitizing effect on the cancer cells which enhanced their antiproliferative potency, a finding which is crucial for the anti-proliferative potency of the novel synthetic di-tert-butyl phenol based dual COX–LOX inhibitors in colon cancer cells.     

Syntheses and characterization of nimesulide derivatives for dual enzyme inhibitors of both cyclooxygenase-1/2 and 5-lipoxygenase

Cyclooxygenase-1/2 (COX-1/2) and 5-lipoxygenase (5-LOX) are enzymes in two different pathways in the inflammatory process. In the present study, a variety of new nimesulide derivatives were synthesized through incorporation of a 5-LOX pharmacophore into nimesulide followed with some structural modifications, which were then characterized for dual enzyme inhibitors for these two types of enzymes. Their structure-activity relationships (SARs) were studied, and compound 20f was found to be an excellent dual enzyme inhibitor. Its binding conformation and interaction mode were studied with molecular docking experiments. Compound 20f could become a lead compound for further development for potential anti-inflammatory drugs.     

Synthesis and 5-lipoxygenase inhibitory activity of new cinnamoyl and caffeoylclusters

Novel cinnamoyl and caffeoyl clusters were synthesized by multiple Cu(I)-catalyzed [1,3]-dipolar cycloadditions and their anti-5-lipoxygenase inhibitory activity was tested. Caffeoyl cluster showed an improved 5-lipoxygenase inhibitory activity compared to caffeic acid, with caffeoyl trimer 16 and tetramer 19 showing the best 5-lipoxygenase inhibitory activity.     

Synthesis of celecoxib analogs that possess a N-hydroxypyrid-2(1H)one 5-lipoxygenase pharmacophore: biological evaluation as dual inhibitors of cyclooxygenases and 5-lipoxygenase with anti-inflammatory activity

A hitherto unknown class of celecoxib analogs was designed for evaluation as dual inhibitors of the 5-lipoxygenase/cyclooxygenase-2 (5-LOX/COX-2) enzymes. These compounds possess a SO(2)Me (11a), or SO(2)NH(2) (11b) COX-2 pharmacophore at the para-position of the N(1)-phenyl ring in conjunction with a 5-LOX N-hydroxypyrid-2(1H)one iron-chelating moiety in place of the celecoxib C-5 tolyl group. The title compounds 11a-b are weak inhibitors of the COX-1 and COX-2 isozymes (IC(50)=7.5-13.2 microM range). In contrast, the SO(2)Me (11a, IC(50)=0.35 microM), and SO(2)NH(2) (11b, IC(50)=4.9 microM), compounds are potent inhibitors of the 5-LOX enzyme comparing favorably with the reference drug caffeic acid (5-LOX IC(50)=3.47 microM). The SO(2)Me (11a, ED(50)=66.9 mg/kg po), and SO(2)NH(2) (11b, ED(50)=99.8 mg/kg po) compounds exhibited excellent oral anti-inflammatory (AI) activities being more potent than the non-selective COX-1/COX-2 inhibitor drug aspirin (ED(50)=128.9 mg/kg po) and less potent than the selective COX-2 inhibitor celecoxib (ED(50)=10.8 mg/kg po). The N-hydroxypyridin-2(1H)one moiety constitutes a novel pharmacophore for the design of cyclic hydroxamic mimetics capable of chelating 5-LOX iron for exploitation in the design of 5-LOX inhibitory AI drugs.     

Disulfiram is a potent inhibitor of rat 5-lipoxygenase activity

The effect of disulfiram on the 5-lipoxygenase activity from rat polymorphonuclear leukocyte cell-free lysates was determined and compared with that of other thiocarbamoyl and aryl disulfides. Disulfiram was a potent inhibitor of the soluble 5-lipoxygenase causing 50% inhibition at submicromolar concentrations (0.4-0.7 microM). The inhibition by disulfiram was similar to that of bis(diisopropylthiocarbamoyl) disulfide with both compounds being about 100-fold more potent as inhibitors than the structurally related bis(4-methyl-1-homopiperazinylthiocarbonyl) disulfide analog. The potency of 5-lipoxygenase inhibition by disulfiram was comparable to that of diphenyldisulfide (IC50 = 0.2-0.4 microM), in the same range or better than most typically used inhibitors. However, the degree of inhibition by disulfiram was more sensitive to thiols than that of diphenyldisulfide, as shown by the selective protection against disulfiram inhibition by low concentrations of thiols. Diethyldithiocarbamate, the reduction product of disulfiram, was a less potent inhibitor of the 5-lipoxygenase activity, causing only a partial inhibition (40-60%) over a wide range of concentrations (2-30 microM). The results demonstrate that disulfiram is a potent inhibitor of 5-lipoxygenase in vitro and provide the basis for further investigations on the effect of the drug on leukotriene biosynthesis inhibition and its contribution to the ethanol-disulfiram reaction. They also indicate that disulfiram represents a sensitive reagent to characterize the thiol requirement of the 5-lipoxygenase reaction.     

Design, synthesis and biological evaluation of benzo[1.3.2]dithiazolium ylide 1,1-dioxide derivatives as potential dual cyclooxygenase-2/5-lipoxygenase inhibitors

3-(4-Bromophenyl)-6-nitrobenzo[1.3.2]dithiazolium ylide 1,1-dioxide (5) was discovered as a new prototype for dual inhibitors of cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX). Thus, the structure-activity relationships of benzo[1.3.2]dithiazolium ylide 1,1-dioxide skeleton were carried out. The 6-NO(2) group played an essential role in the inhibitory activity. In addition, moderate-sized lipophilic substituents at the para-position of the 3-aryl moiety were required for dual COX-2/5-LOX inhibitory activity. Among the identified potent dual inhibitors, 3-(4-tbutylphenyl) derivative 30c (IC(50) values of 0.27 μM and 0.30 μM against COX-2 and 5-LOX, respectively) and 3-(4-biphenyl) derivative 30f (IC(50) values of 0.50 μM and 0.15μM against COX-2 and 5-LOX, respectively) were the most potent dual COX-2/5-LOX inhibitors. Intraperitoneal administration of 30c at 100mg/kg demonstrated potent acute anti-inflammatory activity. As a result, benzo[1.3.2]dithiazolium ylide 1,1-dioxide represented a novel scaffold for the exploitation in developing dual COX-2/5-LOX inhibitors.     

Phenylsulphonyl urenyl chalcone derivatives as dual inhibitors of cyclo-oxygenase-2 and 5-lipoxygenase

Two series of phenylsulphonyl urenyl chalcone derivatives (UCH) with various patterns of substitution were tested for their effects on nitric oxide (NO) and prostaglandin E2 (PGE2) overproduction in RAW 264.7 macrophages. None of the tested compounds reduced NO production more than 50% at 10 microM but most of them inhibited the generation of PGE2 with IC50 values under the micromolar range. Me-UCH 1, Me-UCH 5, Me-UCH 9, Cl-UCH 1, and Cl-UCH 9 were selected to evaluate their influence on human leukocyte functions and eicosanoids generation. These derivatives selectively inhibited cyclo-oxygenase-2 (COX-2) activity in human monocytes being Me-UCH 5 the most potent (IC50 0.06 microM). Selected compounds also reduced leukotriene B4 synthesis in human neutrophils by a direct inhibition of 5-lipoxygenase (5-LO) activity, with IC50 values from 0.5 to 0.8 microM. In addition, lysosomal enzyme secretion, such as elastase or myeloperoxidase as well as superoxide generation in human neutrophils were also reduced in a similar range. Our findings indicate that UCH derivatives exert a dual inhibitory effect on COX-2/5-LO activity. The profile and potency of these compounds may have relevance for the modulation of the inflammatory and nociceptive responses with reduction of undesirable side-effects associated with NSAIDs.     

Essential structural profile of a dual functional inhibitor against cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX): molecular docking and 3D-QSAR analyses on DHDMBF analogues

It is recently proposed that compounds with equal capabilities of inhibiting COX and 5-LOX, both are key enzymes involved in the arachidonic acid (AA) cascade, are expected to be safer non-steroidal anti-inflammatory drugs (NSAIDs). To dig out helpful information in designing dual functional inhibitors against the two enzymes, homology modeling, molecular dynamics (MD) simulations, automated docking, and 3D-QSAR analyses were performed in this study on 21 COX-2/5-LOX dual inhibitors, namely, 7-tert-butyl-2,3-dihydro-3,3-dimethylbenzofuran (DHDMBF) analogues. A 3D-model of 5-LOX was built based on the high-resolution X-ray structure of rabbit reticulocyte 15-lipoxygenase. Molecular docking was then applied to locate the binding orientations and conformations of DHDMBF analogues with COX-2 and 5-LOX, respectively, leading to highly predictive CoMFA models constructed on the basis of the binding conformations with q2 values of 0.782 and 0.634 for COX-2 and 5-LOX, respectively. In addition, CoMFA field distributions were found in good agreement with the structural characteristics of the corresponding binding sites. Both the docking simulations and QSAR analyses suggest that new potent dual inhibitors should share a structural feature with a moderately bulky group at R2 position and a rather negatively charged group around the position of the carbonyl group of DHDMBFs. Therefore, the final 3D-QSAR models and the information of the inhibitor-enzyme interaction should be useful in developing new NSAIDs as anti-inflammation drugs with favorable safety profile.     

Synthesis and biological evaluation of a class of 5-benzylidene-2-phenyl-thiazolinones as potent 5-lipoxygenase inhibitors

A class of 5-lipoxygenase (5-LO) inhibitors characterized by a central 5-benzylidene-2-phenyl-thiazolinone scaffold was synthesized as a new series of molecular modifications and extensions of a previously reported series. Compounds were tested in a cell-based and a cell-free assay and furthermore evaluated for their influence on cell viability. The presented substituted thiazolinone scaffold turned out to be essential for both the 5-LO inhibitory activity and the non-cytotoxic profile. With (Z)-5-(4-methoxybenzylidene)-2-(naphthalen-2-yl)-5H-thiazol-4-one (2k, ST1237), a potent, direct, non-cytotoxic 5-LO inhibitor with IC(50) of 0.08 μM and 0.12 μM (cell-free assay and intact cells), we present a promising lead optimization and development for further investigations as novel anti-inflammatory drug.     

Effects of tepoxalin, a dual inhibitor of cyclooxygenase/5-lipoxygenase, on events associated with NSAID-induced gastrointestinal inflammation

Prostaglandins and thromboxanes are products of arachidonic acid metabolism via the cyclooxygenase (CO) enzyme and are responsible for the pain and swelling common to sites of inflammation. Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit the production of these substances and are used in the treatment of inflammatory diseases such as arthritis. However, one of the major side-effects of NSAID therapy is gastric ulceration. It is possible that inhibition of prostaglandin production and a related increase in the formation of leukotrienes via the 5-lipoxygenase (5-LO) enzymatic pathway are responsible for attracting inflammatory cells, causing local sites of inflammation and producing ulceration. To determine the effects of 5-LO inhibition on this hypothesis, studies were performed in rats to evaluate the effects of tepoxalin, a dual CO/LO inhibitor on leukotriene B₄ levels in gastric mucosa and neutrophil adhesion in mesenteric venules. In rats, chronic oral administration of an NSAID, indomethacin (2 mg/kg daily over 4 days), resulted in 40% mortality, accompanied by intestinal adhesions and perforations when evaluated 24 h after the fourth dose of drug. Additionally, neutrophil adhesion was increased in the mesenteric venules and cell infiltration was evident in the mesenteric interstitium. These gastrointestinal side-effects were inhibited in a separate group of rats administered tepoxalin (20 mg/kg, p.o) 30 min prior to each daily indomethacin treatment. Further studies were performed to determine tepoxalin's effects on early events associated with NSAID-induced gastrointestinal inflammation, including neutrophil adhesion, lipid peroxide generation and LTB₄ production. Indomethacin (100 mg/kg, p.o.) produced elevated levels of LTB₄ in rat gastric mucosa 90 min after administration. Additionally, neutrophil adhesion in mesenteric venules was increased at this dose and with the administration of another NSAID, naproxen. No generation of lipid peroxides was evident in the gastric mucosa at this timepoint. Tepoxalin (up to 400 mg/kg, p.o.) did not have an effects on gastric mucosal LTB₄ generation and lipid peroxide levels. A decrease in neutrophil adhesion was observed at the highest dose. In another study, pretreatment with tepoxalin (ED₅₀=7.5 mg/kg, p.o.) or the selective 5-LO inhibitor zileuton (100 mg/kg, p.o.) prevented the increases in gastric mucosal LTB₄ levels and neutrophil adhesion induced by indomethacin (100 mg/kg, p.o.). These data suggest that LO inhibition may play a vital role in the prevention of NSAID-induced gastric inflammation, providing insight into the lack of ulcerogenicity with tepoxalin and new approaches to anti-inflammatory therapy which may prevent gastric side effects.     

Synthesis and cytotoxic activity of a new potent daunomycinone derivative

The preparation and cytotoxic activity of 4′-azido-3′-bromo-3′-deamino-4′-deoxydaunorubicin is described. The new compound was found to be less active in vitro than adriamycin against L1210 and the sensitive cell lines KB-3-1 and MES-SA, but retained interesting cytotoxicity against the adriamycin resistant subline KB-A1 and the multidrug resistant MES-SA/Dx5 subline.     

Phenylacetic acid regioisomers possessing a N-difluoromethyl-1,2-dihydropyrid-2-one pharmacophore: Evaluation as dual inhibitors of cyclooxygenases and 5-lipoxygenase with anti-inflammatory activity

A novel class of phenylacetic acid regioisomers possessing a N-difluoromethyl-1,2-dihydropyrid-2-one pharmacophore attached to its C-2, C-3 or C-4 position was designed for evaluation as anti-inflammatory (AI) agents. A number of compounds exhibited a combination of potent in vitro cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX) inhibitory activities. 2-(1-Difluoromethyl-2-oxo-1,2-dihydropyridin-4-yl)phenylacetic acid (9a) exerted the most potent AI activity among this group of compounds. Molecular modeling studies showed that the N-difluoromethyl-1,2-dihydropyridin-2-one moiety present in 9a inserts into the secondary pocket present in COX-2 to confer COX-2 selectivity, and that the N-difluoromethyl-1,2-dihydropyrid-2-one group (9a) binds close to the region of the 15-LOX enzyme containing catalytic iron (His361, His366). Accordingly, the N-difluoromethyl-1,2-dihyrdopyrid-2-one moiety possesses properties that make it an attractive pharmacophore suitable for the design of dual COX-2/5-LOX inhibitory AI drugs.     

Novel N-substituted 5-aminosalicylamides as dual inhibitors of cyclooxygenase and 5-lipoxygenase enzymes: Synthesis,biological evaluation and docking study

Three new series of 5-aminosalicylic acid derivatives; series I (14, 16–18), series II (19–30) and series III (31–41) were synthesized as potential dual COX-2/5-LOX inhibitors. Their chemical structures were confirmed using spectroscopic tools including IR, ¹H NMR, ¹³C NMR, mass spectroscopy and elemental analyses. The anti-inflammatory activity for all target compounds was evaluated in vivo using carrageenan-induced paw edema. Compound 36 showed the highest anti-inflammatory activity (114.12%) relative to reference drug indomethacin at 4 h interval. Selected derivatives were evaluated in vitro to inhibit ovine COX-1, human recombinant COX-2 and 5-LOX enzymes. Compounds 34 & 35 exhibited significant COX-2 inhibition (IC₅₀ = 0.10 µM) with significant COX-2 selectivity indices (SI = 135 & 145 respectively) approximate to celecoxib (IC₅₀ = 0.049 µM, SI = 308.16) and exceeding indomethacin (IC₅₀ = 0.51 µM, SI = 0.08). Interestingly, all compounds showed superior 5-LOX inhibitory activity about 2–5 times relative to zileuton. Compound 16 was the superlative 5-LOX inhibitor that revealed (IC₅₀ = 3.41 µM) relative to zileuton (IC₅₀ = 15.6 µM). Compounds 34, 35, 36 and 41 showed significant dual COX-2/5-LOX inhibitions. The gastric ulcerogenic effect of compound 36 was examined on gastric mucosa of albino rats and they showed superior GI safety profile compared with indomethacin. Molecular docking studies of the compounds into the binding sites of COX-1, COX-2 and 5-LOX allowed us to shed light on the binding mode of these novels dual COX and 5-LOX inhibitors.     

Synthesis and evaluation of benzoxazole derivatives as 5-lipoxygenase inhibitors

5-Lipoxygenase (5-LOX) is important enzyme in the biosynthesis of leukotrienes, and is a potential target in the treatment of asthma and allergy. We designed and synthesized a series of benzoxazoles and benzothiazoles as 5-LOX inhibitors. Fourteen compounds prepared showed the inhibition of LTC4 formation with IC₅₀ value of 0.12–23.88 μM. Also two compounds 2d and 2g showed improved airway hypersensitiveness.     

Synthesis and pharmacological characterization of a new benzoxazole derivative as a potent 5-HT3 receptor agonist

N-(2-Benzoxazol-2-yl-ethyl)-guanidine hydrochloride (10) was synthesized and pharmacologically tested. This compound showed high affinity for the 5-HT(3) receptor (K(i)=0.77 nM) and potently triggered the von Bezold-Jarisch reflex (BJR) in rats with an ED(50)=0.52 microg/kg iv and intrinsic activity next to 1 (i.a.=0.94). This stimulant effect was abolished by pretreatment with the 5-HT(3) receptor antagonist granisetron and was subject to a rapid and pronounced tachyphylaxis, due to desensitization of the peripheric cardiac 5-HT(3) receptor. Consequently, 10 acts as an in vivo 5-HT(3) antagonist inhibiting the BJR responses evoked by submaximal doses of 5-HT with an ID(50)=5.8 microg/kg iv.     

Synthesis of oxazolidinone phospholipid analogue as a new inhibitor of phospholipase A2

(S)- and (R)-3-dodecanoyl-4-phosphatidylcholinohydroxymethyl-2-oxazolidinone (1), which are cyclic analogues of the amide phospholipid 7, were synthesized. The inhibitory activities of these analogues toward phospholipase A₂ were compared with that of the amide analogue 7.     

Synthesis of reversed hydroxamic acids of indomethacin: dual inhibitors of cyclooxygenase and 5-lipoxygenase

Replacement of the carboxylic acid function of inodmethacin with reversed hydroxamic acids converted this selective cyclooxygenase (CO) inhibitor into dual inhibitors of CO and 5-lipoxygenase (5-LO).     

Synthesis and activity of sulfonamide-substituted 4,5-diaryl thiazoles as selective cyclooxygenase-2 inhibitors.

A series of sulfonamide-substituted 4,5-diarylthiazoles was prepared via three synthetic routes as selective COX-2 inhibitors. Recently in the synthesis of selective COX-2 inhibitors we have discovered that the sulfonamide moiety is a suitable replacement for the methylsulfonyl moiety yielding compounds with activity both in vitro and in vivo.     

Synthesis of 5-ethynyl-2'-deoxyuridine-5'-boranomono phosphate as a potential thymidylate synthase inhibitor

The 5-ethynyl-2'-deoxyuridine nucleoside and the 5'-boranomonophosphate nucleotide were synthesized as analogs of 5-fluoro-2'-deoxyuridine monophosphate (5-FdUMP), a widely used mechanism-based inhibitor of thymidylate synthase. Synthesis was carried out from protected 5-iodo-2'-deoxyuridine and trimethylsilylacetylene by Sonogashira palladium-catalyzed cross coupling reaction followed by selective phosphorylation and finally boronation.